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Copy path167. Two Sum II - Input array is sorted.js
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Copy path167. Two Sum II - Input array is sorted.js
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66 lines (59 loc) · 1.72 KB
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/**
Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number.
The function twoSum should return indices of the two numbers such that they add up to the target, where index1 must be less than index2.
Note:
Your returned answers (both index1 and index2) are not zero-based.
You may assume that each input would have exactly one solution and you may not use the same element twice.
Example:
Input: numbers = [2,7,11,15],>
Output: [1,2]
Explanation: The sum of 2 and 7 is 9. Therefore index1 = 1, index2 = 2.
*/
/**
* Algorithm: Two pointers
*
* T: O(n)
* S: O(1)
*/
/**
* @param {number[]} numbers
* @param {number} target
* @return {number[]}
*/
const twoSum = function(numbers, target) {
let start = 0;
let end = numbers.length - 1;
let result = [];
while (start < end) {
if (numbers[start] + numbers[end] === target) {
result.push(start + 1);
result.push(end + 1);
break;
}
else if (numbers[start] + numbers[end] > target) {
end -= 1;
} else {
start += 1
}
}
return result;
};
/**
* Leetcode Fundamental: 11/6 Update
*/
/**
* @param {number[]} numbers
* @param {number} target
* @return {number[]}
*/
var twoSum = function(numbers, target) {
if (numbers === undefined || numbers.length === 0 || target === undefined) return [];
let left = 0;
let right = numbers.length - 1;
while (left < right) {
if (numbers[left] + numbers[right] < target) left += 1;
else if (numbers[left] + numbers[right] > target) right -= 1;
else return [left+1 , right+1];
}
return [];
};